This invention relates to marking compositions for use in writing implements such as pencils. More specifically, this invention relates to an improved flexible marking composition for use in a permanently flexible pencil.
There has existed in the prior art a need for a flexible marking composition for a pencil. Such a composition desirably would be extrudable into an elongated, thin rod-like shape for reception within a flexible pencil body formed from a suitable plastic or the like to provide a permanently flexible pencil. This flexible pencil would be advantageous in that the composition and the pencil body would resist breakage during use, while still providing a marking material which can be readily sharpened. Moreover, such a pencil would have particular novelty attraction in that the flexible pencil could be oriented by the user in virtually any geometric configuration.
Several attempts have been made in the prior art to produce a flexible marking composition for a pencil. These prior art compositions essentially have comprised a combination of a flexible elastomer material with a suitable pigment. However, in the prior art, these compositions have tended to harden or become brittle with age, or upon exposure to ambient temperature fluctuations, thereby reducing the necessary flexibility of the composition. In the prior art, this has resulted in flexible marking compositions for pencils which tend to break easily after a relatively short period of time.
The present invention overcomes the problems and disadvantages of the prior art by providing an improved flexible marking composition which does not lose its flexibility over time, and which is resistant to the effects of ambient temperature variations.